turned opencv_stitching application to module and sample

modules/stitching/src/camera.cpp

@@ -0,0 +1,20 @@
+#include "precomp.hpp"
+
+using namespace std;
+
+namespace cv
+{
+
+CameraParams::CameraParams() : focal(1), R(Mat::eye(3, 3, CV_64F)), t(Mat::zeros(3, 1, CV_64F)) {}
+
+CameraParams::CameraParams(const CameraParams &other) { *this = other; }
+
+const CameraParams& CameraParams::operator =(const CameraParams &other)
+{
+    focal = other.focal;
+    R = other.R.clone();
+    t = other.t.clone();
+    return *this;
+}
+
+} // namespace cv